Lottery games of the above-mentioned type are well known. The player selects numbers from within the allowed range of say 1 to 49 to form one or more combination of 6 numbers. Cards are filled out with the selected combinations and presented to a lottery office taking stakes. After the draw, normally on a weekly basis, the winners of the full combination of 6 numbers share the main prize and subsidiary prizes are won by the players whose bets comprise winning sub-combinations of 5 numbers plus the bonus number (5/6+, if applicable), or of 5 numbers (5/6 prize group), or of 4 numbers (4/6 prize group), and usually much lesser amounts are won by those having selected combinations comprising only 3 winning numbers (3/6) prize group), by far the easiest prizes to win.
These lottery games may be more generally expressed as m/k where m is the amount of distinct numbers forming a combination C.sub.j the distinct numbers being chosen from an array of consecutive numbers ranging from 1 to k. In a 6/49 lottery, k equals 49 and m equals 6. The 6/49, 6/44 and the 6/36 lotteries are quite common and they are among the most popular legal lotteries.
Devices for randomly generating combinations of numbers to be used in these lottery games are already known. These known devices operate either electronically or mechanically and can be of various types and sizes. An example of such a device is described in U.S. Patent to Harrington et al U.S. Pat. No. 4,151,404 issued on Apr. 24, 1979.
These prior devices suffer from a major drawback in that they operate only in the random mode, and consequently the user has no control over the selection process. Numerous players prefer to use certain favorite numbers in the combinations on which they place their stakes. These favorite numbers may be, for example, the user's date of birth or any sets of numbers that the player wishes to adopt when placing his stakes. Since the prior art devices operate in a random selection mode only, they do not generate combinations containing pre-selected or favourite numbers and therefore they do not allow for the user's input.
Furthermore, when the user wishes to bet numerous combinations in a given draw, it is desirable to use a device which will generate the combinations according to a methodological approach for eliminating at least some degree of redundancy among the played combinations. This is quite useful when a person (or group of players) decides to invest on say 100 combinations with the intention of winning subsidiary prizes without eliminating the chances for a main size.